In this year, we were focused on two major sub-projects. First, we employed glutamate-sensitive sensors coupled with high-speed amperometry to evaluate rapid changes in glutamate following exposure to natural arousing stimuli, cocaine and nicotine. Second, we employed glucose-sensitive sensors coupled with high-speed amperometry to evaluate rapid fluctuations in brain glucose levels following exposure to natural stimuli and drugs of abuse (cocaine and nicotine). This work will be expanded during the next years to include more complicated behavioral paradigms that involve the use of addictive drugs.